Semiochemical reservoir to attract subterranean termites tunneling in soil

ABSTRACT

The present invention relates generally to polymer devices impregnated with semiochemical attractants for termites. The materials for delivering the semiochemicals are preferably cellulose-free. Devices of the subject invention are placed in soil and provide a slow-release and permeation of the semiochemicals into the adjacent soil so that termites tunneling in the vicinity are directed toward the chemical sources. Because the semiochemicals are impregnated in the polymer, the device also protects the semiochemicals so that they do not degrade rapidly under field conditions. In a preferred embodiment, the subject invention comprises a durable station housing, preferably with a removable bait, wherein the body of the station housing itself is impregnated with a semiochemical attractant.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of co-pending Application U.S. Ser. No.11/638,154, filed Dec. 13, 2006, now U.S. Pat. No. 8,603,510; which is adivisional application of U.S. Ser. No. 10/392,798, filed Mar. 19, 2003(now U.S. Pat. No. 7,169,403); which claims the benefit of U.S.Provisional Application No. 60/366,830, filed Mar. 22, 2002; all ofwhich are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

One relatively recent development in termite control is the use ofslow-acting toxicants for managing subterranean termite populations nearstructures. Many chemical “attractants” (pheromones and the like) havebeen proposed for use in such baits. See, e.g., WO 93/23998 and U.S.Pat. No. 5,571,967. However, there have been few if any demonstrationsof true “attraction” of subterranean termites that forage in soil. Theterm “attractant” is often confused with or misused in place of “feedingstimulant,” or “arrestant” (which are chemical cues that cause theanimals to aggregate near the chemical source). An “attractant” is “achemical that causes animals to make orientated movement toward itssources” (Shorey, 1977). Semiochemicals are chemical substances thatdeliver behavioral messages to animals (Metcalf & Metcalf, 1975).

There are many patents that refer to the use of feeding stimulants incellulose-based baits to increase termite feeding on baits. Some of thepatents refer to “attractants,” but the data and proposed uses indicatethat they actually involve “feeding stimulants” that increase termitefeeding on baits rather than attractants that cause termites to “makeorientated movement toward its sources.” For example, U.S. Pat. No.6,093,389 relates to a steroid derivative in a cellulose-based termitebait. This reference states that the use of decayed or fungus-inoculatedwood to attract termites is not satisfactory for commercial use. A foodsource is said to be an important component in the bait compositions ofthis patent.

U.S. Pat. No. 5,874,097 relates to the use of chemicals (naphthalene andothers similar to nest extracts; identified in PAPERMATE ball-point pensthat were found to elicit trail-following behavior in termites) toincrease termite feeding on baits comprising cardboard, paper, sugarcane, corn cobs, and other cellulose mixtures. U.S. Pat. No. 5,637,908uses 2-naphthalenemethanol in cellulose-based baits such as cardboardand paper to induce trail-following behavior and for feeding stimulationto increase the rate of bait consumption by termites. U.S. Pat. No.3,858,346 uses “termite-attracting”carbohydrate(hexachlorocyclo-pentadiene dimer) in sawdust-based bait toincrease termite feeding of baits.

Rust et al., Sociobiology, Vol. 28, No. 3, pp. 275-285 (1996), discussattempts to use extracts of brown-rot fungus to increase the likelihoodthat wood stakes would be located by termites. Water was used in anattempt to disperse the extract in sand. It was noted that the extractwas not soluble enough in water, and surfactants were used in an attemptto improve the effective depth that the fungal extract would penetratethe soil. Field studies of sweetgum blocks conditioned with theGloecophyllum trabeum fungus “did not reveal any specialattractiveness.” The conclusion of this reference was that additionalresearch is needed to insure the longevity and maximal dispersion ofsuch attractants in soil.

U.S. Pat. No. 6,203,811 uses a fungal extract as a “feeding stimulant”in cellulose-based baits to increase termite feeding on the baits.

Various patents relate to the feeding stimulants in wood blocks togetherwith a slow-acting insecticide. Again, some of these patents might usethe term “attractant,” but the data and proposed use indicate they donot and are not intended to “cause termites to make orientated movementtoward its sources.” Thus, these are examples of “feeding enhancers.”U.S. Pat. No. 4,455,441 uses an “attractant termiticide” compound in afeeding block. U.S. Pat. No. 3,070,495 places wood blocks treated withfungi-decay extract and an insecticide in the ground; this might resultin increased termite feeding but did not “attract” subterranean termitesfrom any distance. U.S. Pat. No. 4,363,798 uses fungi-decayed woodblocks impregnated with borons (to kill termites).

In most or all of the art mentioned above, feeding stimulants or other“attractive” semiochemicals are incorporated in toxic baits, which arenot intended for “monitoring.” U.S. Pat. No. 5,573,760 teaches acomposition “preferred” by termites that is to be used for monitoringtermites in soil before toxicant baits are installed. The data showedthat the medium was “highly palatable” but did not demonstrate that itcaused termites foraging in soil “to make orientated movement toward itssources.” Thus, that medium functioned as a feeding stimulant ratherthan as an “attractant.” The following portion from that patent clearlyillustrates the difference between “attractants” and feeding stimulants:

It is important to note that the monitoring composition does not attracttermites per se. One would not want to attract termites and create aproblem where none existed before. However, because termites preferconsuming the monitoring composition, once the termites discover it,they will return to it and recruit others from the colony. Subterraneantermites tunnel underground and will tunnel into the monitoringcomposition. The termites will stimulate other colony members to use thefood, then return to the colony and share the food. These behavioralpatterns are utilized to great advantage in the monitoring andcontrolling methods of the present invention.

Consistent with this, the art heretofore taught that a cellulose-basedfood source was an essential element to make the baits sufficiently“attractive” to termites (even if pheromone “attractant” is also used).While the art mentions the use of pheromones to make baits moreattractive, the art generally teaches that a cellulose/food source isneeded in conjunction with the pheromone. U.S. Pat. No. 5,151,443mentions that trail pheromones and decayed wood can be used with sawdustand the like in baits for controlling termites. U.S. Pat. No. 6,100,805relates to a spike-shaped tube for termite detection. A conductive loopis present between two wooden blocks inside the tube. A pheromone can beformed over or blended within “electrically insulative protectivematerial” that covers the conductive loop. The insulation can be a resinsuch as an epoxy resin, including two-part epoxy resins. However, thewooden blocks are treated as essential components. Apparently, acellulose food source was deemed to be essential as an “attractant.”U.S. Pat. No. 5,571,967 relates to a termite-detecting electronicdevice. The device as illustrated has a can-like outer “casing” that isto be positioned primarily above ground. A wooden detecting sample (acube of wood) is within the “casing.” As the detecting block isdegraded, presumably by termites, such movement is detected by theelectronic apparatus. The '967 patent states that a termite-guidingpheromone is used in order to “attract” termites to the detectingsample.

However, one major obstacle to the successful “real world” use ofcellulose-based medium or baits that are placed in soil is theirrelatively short life. Thus, these references do not even identify amain problem with pheromones and cellulose-based baits: especially whenused in hot and humid soil, the chemical attractants therein decomposetoo quickly to be of practical use for “attractant” delivery. It wouldbe particularly advantageous to have monitoring devices that would lastafter eliminating the structure-infesting populations by the initialbaiting, in which months or years may pass before new populations ofsubterranean termite migrate near the stations. Under thesecircumstances, an “attractant” would need to remain available in soilfor months and sometimes years.

For commercial monitoring-baiting programs, the monitoring devices mayhave to remain in soil for 6-18 months before termites are detected inthe stations. Most commercial baiting programs, such as the SENTRICON®Termite Colony Elimination System, involve a monitoring-baitingprocedure that depends on the monitoring phase to detect termites beforetoxic baits are used.

There are other issues to be addressed in order to successfully usepheromones and baits. For example, U.S. Pat. No. 5,572,825 relates to aglue trap primarily for trapping cockroaches and the like. This patentacknowledges that aggregation pheromones might be used but notes thatthere are associated difficulties, such as identifying andcharacterizing a desired pheromone (which can be colony-specific) andmaintaining the stability of such volatile hormones.

WO 93/23998 mentions the use of bait materials such as METHOCEL in acasing in a station housing. This application also states thatpheromones (and the like) can be used to modify the monitoring device toincrease the possibility that the target pest will enter and move withinthe device. However, it is also noted therein that trail pheromones canactually cause foraging termites to avoid eating the bait, and thatreproducing functional synthetic pheromones can be very difficult(especially in light of the observation that different pheromones can bepest and colony specific).

U.S. Pat. No. 5,024,832 showed that the (3Z, 6Z, 8E)-dodecatrienol has aunique characteristic of inducing termite trail-marking. The embodimentdescribed therein involved detecting and capturing foraging termites byplacing a glass plate coated with this trail-marking pheromone on thesurface of the soil. As with many behavior-modifying semiochemicals,however, (3Z, 6Z, 8E)-dodecatrienol is unstable in soil or in open air(as it reacts with oxygen). It thus degrades too quickly for practicaluse.

U.S. Pat. Nos. 6,079,151 and 6,058,646 discuss in more detail thespecies- and colony-specific nature of pheromones, as well as thedifference between trail and feeding-initiating pheromones. Theembodiments illustrated in these patents appear to be above-ground boxesfor mounting to a structure. These patents state that pheromone mimicscan make the matrix attractive or non-repellent to the pest speciesbeing monitored or controlled.

Some attempts have been made to attract termites without pheromones.U.S. Pat. No. 6,023,879 describes a device to deliver water in soil nearbait stations to attract termites. U.S. Pat. No. 5,921,018 teaches anelaborate apparatus to collect and channel rainwater in soil near baitstations to capture and kill termites. U.S. Pat. No. 5,899,018 describesa device that uses the solar heating/night cooling cycle to deliver amoisture-absorbing “attractant” (cardboard, cow dung, wood, and thelike) into soil to attract termites. On the other hand, U.S. Pat. No.5,927,001 relates to a bait station having a tubular body (made of rigidfoam or plastic like Styrofoam) with a triangular cross section; atriangular bait is fitted into the bait holder. The bait holder isdesigned to keep water away from the cardboard to prevent itsdegradation. The bait is impregnated with a toxicant. Pheromones are notmentioned in this patent.

U.S. Pat. No. 6,158,166 includes a discussion of materials that can beused as termite bait. Rigid foam such as Styrofoam is one suggestion.However, it is clearly noted therein that such materials are not actualfood sources and thus are to be used in conjunction with natural woodproducts.

U.S. Pat. No. 4,043,073 relates to a container that encloses baitmaterial for termites or other pests, wherein the bait has an odiferousmaterial in it to signal to humans when the container has been attackedby pests. This patent mentions that a hormone can be added as anattractant to the container wall. These containers appear to be“permanently” buried in the ground without having the bait replaced.This patent does not teach or suggest the combination of advantages thatusing a pheromone in a SENTRICON-like housing would provide. While thispatent, like many others, mentions hormones, this patent does not showany actual success of doing so.

U.S. Pat. No. 5,141,744 relates to a macrogel that can be in the form ofa cone, funnel, tube, or spike wherein the macrogel contains anentomopathogen attractant such as fungal-decayed wood. U.S. Pat. No.5,504,142, entitled “Device for Controlling Insects,” relates to amixture comprising a thermoplastic elastomer and at least one chemicalmediator (including pheromones) that acts on the behavior of insects andacarids. The invention is designed for treating crops against insectsand acarids. The mixture can take the form of granules or sticks.

The '142 patent cites Japanese Application 81 JP-024042, published asKOKAI JP 57 139005, as describing compositions of pheromones and of abinder containing 4 to 20% of pheromones. The binder is silicone or SBRrubber. A solvent such as methylene chloride, benzene, an alcohol, etc.and fillers such as cellulose, silica, active carbon, or carbonate arealso used. The product is in paste form.

The '142 patent also cites U.S. Pat. No. 5,142,817 as describing sheetsor strips formed of a sheet of water-insoluble polymer adhesively bondedto a sheet of a hydrophilic matrix. This matrix may be made of cellulosefibers, polyester, polyacetate, polyvinyl alcohol, or polyoxyethyleneglycol. This matrix contains a plasticizer such as polyoxyethyleneglycol or a sorbitol solution and also a biologically active product.These strips serve to envelop trees. The biologically active product isreleased by a humid atmosphere and serves to protect the trees. Thebiologically active products are stated therein to include pheromones.

Unlike terrestrial insects that live above ground (and can thus orientthemselves using chemical cues that disperse at a distance in theatmosphere), termites tunnel underground in soil. Chemicals do not moveas freely (if at all) in soil as they do in the atmosphere. Much priorart relates to the release of vapor phase pheromones into atmosphere,but vapor does not travel at any significant distance in soil wheresubterranean termites tunneling activity occurs. If a true “attractant”is to be developed for practical use, there is a need to deliver“attractive” agents into the soil so that they cause termites, whenpresent, to “make orientated movement toward its sources.” For example,U.S. Pat. No. 6,216,960 relates to a sustained release pheromonedispenser. This device is intended to disperse synthetic sex pheromonesinto the air to control harmful (flying) insects by disturbing theircopulative communication.

Japanese Patent Application No. 62-177040 (publication no. 64-020853)relates to thermoplastic resin powder and cellulose powder impregnatedwith “a volatile substance.” The compositions of this application aredesigned to effect the gradual release of the “volatile substance.”

U.S. Pat. No. 5.173,535 (Dow Corning) relates to plastic materialshaving particles of crosslinked polymers distributed therein, whichentrap functional materials for the purpose of a controlled release ofthe functional material. The functional materials can includefragrances, pharmaceuticals, dyes, biocides (such as contraceptives),pigments, pesticides, pheromones, and insect repellants. This referencedoes not relate specifically to controlling termites.

There is no prior suggestion in the art that pheromones could beadvantageously incorporated in the housing of a bait station to attractsubterranean termites foraging in soil. Furthermore, the art does notprovide materials that are impregnated with semiochemicals to permittheir release into the soil in adequate amounts for extended periods oftime while being exposed to a range of environmental conditions.

BRIEF SUMMARY OF THE INVENTION

The present invention relates generally to polymer devices impregnatedwith (a high concentration of) a semiochemical attractant for termites.The materials for delivering the semiochemicals are preferablycellulose-free.

Devices of the subject invention are placed in soil and provide aslow-release and permeation of the semiochemicals into the adjacent soilso that termites tunneling in the vicinity are directed toward thechemical sources. Any semiochemicals that can be impregnated into thepolymer for any such purposes are included in this invention. However,those with greater water-solubility are preferred so that they canpermeate out of the polymer reservoir into soil by soil moisture or freewater. The subject invention effectively creates a gradient ofsemiochemicals in soil and thereby causes termites “to make orientatedmovement toward its sources.” Thus, the subject invention provides adevice that can truly deliver “attractants.”

Because the semiochemicals are impregnated in the polymer, the devicealso protects the semiochemicals so that they do not degrade rapidlyunder field conditions. The subject invention thus enables the chemicalgradient to persist in soil for sufficient time so that devices of thesubject invention can be used for practical monitoring programs.Termites in the immediate vicinity follow the gradient to the bait,which can include SENTRICON-like stations.

In a preferred embodiment, the subject invention comprises a durablestation housing, preferably with a removable bait (a bait that can beremoved without substantially disturbing termite foraging tunnels thatlead to the bait), wherein the body of the station housing itself isimpregnated with a semiochemical attractant. Such arrangements helptermites in the immediate area to encounter the bait station tofacilitate earlier detection of such termites. Materials ideally suitedfor use according to the subject invention can be selected in light ofthis disclosure. While impregnated station housings are one preferredembodiment, various other embodiments are exemplified herein; stillothers would be apparent to one skilled in the art having the benefit ofthe subject disclosure. Other examples include sleeves and polymer“chips” that can be placed on and/or near (and/or scattered around) baitstations.

While some prior attempts unsuccessfully tried to use semiochemicals incellulose/wood baits to stimulate termite feeding (of a toxicant), thesubject invention surprisingly and advantageously solves problemsassociated with using cellulose-based baits. Cellulose was heretoforeused in attempts to deliver pheromones to achieve adequate termitecongregation and feeding. The subject invention surprisingly departsfrom the prior teachings, while advantageously (yet counter-intuitively)using materials (heretofore not thought to be possible) that are bettersuited to deliver sufficient levels of semiochemicals into the soil forextended periods of time. Thus, the subject invention relates generallyto the use of cellulose-free materials for delivering pheromones totermites.

The subject invention also provides a novel testing system apparatus.This apparatus enables the identification of semiochemicals that areuseful for termite monitoring and control.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a monitoring station (1) wrapped with a sleeve (2) ofpolymer impregnated with an attractant such as fungal-decay extract.Holes are provided on the sleeve to allow termite entry into thestation. When buried in soil (3), the attractant permeates into the soiland thus creates a gradient of attractant (4) in the soil adjacent tothe station.

FIG. 1B depicts a monitoring station wherein the housing is impregnatedwith an attractant such as fungal-decay extract (5).

FIG. 1C depicts plastic chips (6), impregnated with an attractant suchas fungal-decay extracts, that are buried near a monitoring station sothat the attractants are delivered from the chips into the soil near thestation.

FIG. 2 shows tunneling responses of termites, to treated polymer discsin sand, after being released in a chamber (7) at the center of a2-dimensional foraging area. Released termites were forced to follow anartificial tunnel ending in a staggered physical guide (9). A pair ofpolymer discs, one impregnated with acetone extract of fungus-decayedwood (10) and the other an acetone-only control (11), were placed at 3cm apart in sand near the end of the physical guide. Upon exiting thephysical guide, termite tunneling (12) was “directed” toward the disctreated with fungi-decay extract.

FIG. 3 shows a termite tunnel that departed from the arena edge and was“directed” to a polymer disc impregnated by fungus-decayed wood extract(10). Termite tunneling was not affected by the control discs treatedwith acetone only (11). The distance of “attraction” by the polymer discwas measured between the point where the termite tunnel departed fromthe arena edge (15) and the intercepted disc.

DETAILED DESCRIPTION OF THE INVENTION

The present invention describes polymer devices impregnated with (a highconcentration of) semiochemical attractants for termites. Devices of thesubject invention are placed in soil and provide a slow-release andpermeation of the semiochemicals into the adjacent soil so that termitestunneling in the vicinity are directed toward the chemical sources.Because the semiochemicals are impregnated in the polymer, the devicealso protects the semiochemicals so that they do not degrade rapidlyunder field conditions.

The pheromone-presenting materials of the subject invention aretypically cellulose-free. The subject invention identifies variousadvantages to using a cellulose-free polymer/plastic instead ofimpregnated wood or paper. For example, these types of syntheticmaterials can be impregnated with a higher concentration of theattractant, especially if particularly absorbent materials are selectedfor this purpose. Cellulose-free materials are also more durable andlong-lasting in the environment. Preferred materials are capable ofbeing impregnated with high concentrations of semiochemicals. These andother qualities of the material would allow for long-term dispensationof sufficient amounts of the attractant into the soil. The permeationdynamic is dictated by the concentration of semiochemicals in soil. Asthe serniochemical concentration in soil declines due to degradation,more semiochemicals will permeate out of the polymer sleeve, and thusmaintain the chemical gradient over an extended period.

In a preferred embodiment, as shown in FIG. 1B, the subject inventioncomprises a durable station housing, preferably with a removable bait,wherein the station housing is impregnated with (or otherwise contains)a serniochemical attractant. The station is made more attractive totermites because the material of the outer housing is impregnated withpheromones and the like. Such arrangements help termites in theimmediate area to encounter the bait station to facilitate earlierdetection of such termites. Materials ideally suited for use accordingto the subject invention can be selected for these novel uses. Thestation housing is preferably durable and sturdy. Preferred stationhousings are described in WO 93/23998, but materials for the stationhousing can be optimized for use according to the subject invention.

While impregnated station housings are one preferred embodiment, variousother embodiments are exemplified herein, and still others would beapparent to one skilled in the art having the benefit of the subjectdisclosure. Other examples include sleeves fitted around stationhousings. Polymer “chips” (preferably disks) can also be attached to,placed near, or scattered around bait stations.

In the preferred embodiment where a polymer impregnated withsemiochemicals is used to fabricate the housing of a monitoring stationsuch as the SENTRICON® System, the semiochemicals are protected in thepolymer against degradation. Because the entire station is impregnatedwith the semiochemicals, such embodiments permit a continuous flow ofserniochemical to permeate into the adjacent soil ((4) of FIG. 1B). Thiscreates a lasting serniochemical gradient that causes termites, whenpresent, to make oriented movement toward the impregnated stations.Thus, the effective diameter of the bait station is increased. Ratherthan relying on termites that are already present in an area toencounter the bait station itself, this embodiment of the subjectinvention presents a bait station with an effective width approaching afoot or so because of the “attractive” gradient.

Station housings of the subject application can be made of a variety ofmaterials, such as porous and/or absorbent plastics and other polymers.The housing could be impregnated with feeding-stimulating and/orcongregation pheromones, for example. The pheromone could also bechemically (or otherwise) attached to the station housing instead of, orin addition to, being physically incorporated into the material.

Alternatively, the subject invention also includes a pheromone-ladenmaterial attached to (or associated with) a station housing. Withreference to FIG. 1A, one such preferred embodiment is a sleeve (withholes) made of one of the above-mentioned polymers (2). When placed overa monitoring station (1) and installed in soil, semiochemicalsimpregnated in the polymer sleeve permeate into the soil, and thuscreate a gradient of attractant in the soil adjacent to the station (4).Preferred monitoring stations for use with this embodiment are describedin WO 93/23998, for example. Thus, sleeves of the subject invention canbe shaped like the station housing (at least the portion of the housingthat contacts the ground) and are adapted to fit (snugly) around thehousing.

With reference to FIG. 1C, yet another preferred embodiment is a smallpolymer chip impregnated with semiochemicals (6). When placed in soiladjacent to a monitoring station (1), semiochemicals would permeate fromthe chips into the adjacent soil (4), thus creating a lastingsemiochemical gradient to attract termites toward the vicinity of thestation. Such chips can also be attached to or otherwise associated witha station housing.

In alternative embodiments, the outer-most envelope of the hermeticallysealed baits of U.S. provisional application Ser. No. 60/366,380 (filedMar. 22, 2002; Nan-Yao Su, entitled “Hermetically Sealed Baits forSubterranean Termites”) are embedded with the pheromones according tothe subject invention. “Chips” of the subject invention can also bescattered near such baits.

Devices of the subject application can be used to target any and allsoil dwelling termites, including those of the families Rhinotermitidaeand Termitidae. Also “targetable” are termites of the genusReticulitermes, Coptotermes, Heterotermes, Odontotermes,Microcerotermes, Amitermes, Macrotermes, and Nasutitermes.

In light of the subject disclosure, it will be recognized that variouscomponents can be optimized for particular uses. Thus, the subjectinvention also includes the related use of specific pheromones, housingsmade of specific materials, and the use of materials having specificconcentrations of the associated pheromone(s).

Candidate semiochemicals for use according to the subject inventioninclude, but are not limited to, known trail-following pheromones suchas cis-3, cis-6, trans-8-dodecatrien-1-ol, and related compounds(Matsumura et al. 1969), (3Z, 6Z, 8E)-dodecatrienol, steroidderivatives, 2-naphthalenemethanol, naphthalene and other termite nestextracts, fungi-decayed wood extract, sugars, amino acids, nitrogen-richsubstances such as uric acid, carbohydrates such ashexachlorocyclopentadiene dimers, and others. Polymeric devices of thesubject invention can also be used to absorb/hold feeding stimulants orarrestants, if desired.

Any semiochemicals that can be impregnated into the polymer for any suchpurposes are included in this invention. To facilitate movement ofsemiochemicals by soil moisture or free water, however, water-solublesemiochemicals or their hydrophilic forms are preferred. A preferredembodiment of this invention uses soil moisture or water as a carrier,and thus semiochemicals with high water solubility are preferredcandidates for impregnation in the polymer reservoir. Examples of suchinclude but are not limited to sugars or amino acids, or hydrophilicforms of low water-soluble semiochemicals. Because hydrophilicsemiochemicals are favored, preferred polymers of the subject inventionhave a more porous structure than a typical polymer material. These mayinclude, but are not limited to, high absorbent meltblown polypropylene,filament polyester, polyurethane foams with crosslinked non-linearmolecular network, admixture of polymers such as silicones, urethanes,polyurethane, acrylonitrile butadiene and carriers such as clay oramorphous silica.

Most of the behavior-modifying semiochemicals degrade easily under hightemperature; thus, special considerations are needed when they areimpregnated into the polymeric carrier. Polymeric materials oftenrequire heating during production, but a cool impregnation is apreferred procedure. One example is the use of water-based resin systemssuch as modeling dough that is comprised of gelled poly vinyl alcohol,water, and filler. An alcohol solution of semiochemicals is added to themodeling dough to achieve a semi-liquid consistency which can be formedinto desired sizes and shapes. Upon the evaporation of the alcohol andwater, the poly resin serves to bind the component into a solid anddurable polymer that contains a high concentration of semiochemicals.

Another example of cool impregnation involves diluting an epoxy resinwith an organic solvent (such as acetone) solution of semiochemicals.Upon evaporation of the solvent, a hardener is added to the impregnatedepoxy resin, and it is shaped into desired dimensions.

Microencapsulation procedures may also be used if they do not causeexcessive heating or chemical reactions that would degradesemiochemicals. For example, microencapsulated materials can be mixedwith plastics and molded into a desired shape.

Another option is to use physical impregnation by saturating polymerabsorbents with solutions of semiochemicals. Examples of such absorbentsinclude, but are not limited to, cleanroom wipes made of meltblownpolypropylene, and various grades of absorbent papers made of filamentpolyester. Mesh-like materials can also be used. These non-celluloseabsorbents are made of polymers and will not degrade by exposure tochemicals or microbes. These materials can absorb a large quantity ofsemiochemicals that can be slowly released into adjacent soil.

These procedures are merely exemplary; other procedures can be used toimpregnate a high concentration of semiochemicals into the polymerwithout causing significant degradation of the serniochemical. Onceimpregnated, semiochemicals are protected by the polymer materials, yetsome semiochemicals are slowly released into the adjacent soil to createa serniochemical gradient that causes termites to make oriented movementtoward the sources. The release rate can be manipulated with differenttypes of polymers and the like.

All patents, patent applications, provisional applications, andpublications referred to or cited herein are incorporated by referencein their entirety to the extent they are not inconsistent with theexplicit teachings of this specification.

Following are examples that illustrate procedures for practicing theinvention. These examples should not be construed as limiting. Allpercentages are by weight and all solvent mixture proportions are byvolume unless otherwise noted.

EXAMPLE 1 Preparation of Fungi Decay Extract

Spruce (Picea sp.) boards (13 by 8 by 0.5 cm) were inoculated withbrown-rot fungi, Gloeophyllum trabeum, and stored at 25° C and >90%relative humidity for 1-2 months, during which the wood weight loss dueto fungal decay exceeded 50%. The decayed wooden boards were soaked inan acetone solution for >48 hrs, and the acetone extract was condensedat room temperature to yield the desired concentration.

EXAMPLE 2 Open Air Choice Test

The biological activity of the extract was first tested in a petri dish(9 cm diameter and 1 cm high). Two pieces of filter papers (Whatman No.1, 9 cm diameter) were cut in half and placed side-by-side together inthe petri dish without touching each other. One half of the paperreceived acetone solution of the extract, the other received acetoneonly. Upon the evaporation of the acetone, both filter papers weremoistened with deionized water. Twenty field-collected termites(Coptotermes formosanus) were placed in the dish and the numbers oftermites present on each filter paper piece were counted 1-2 minuteslater. The test was repeated six times. As shown in Table I, mosttermites preferred to aggregate on paper treated with acetone extract offungi decay wood than acetone control, indicating the “arrestant”property of the decay extract.

TABLE I Mean numbers of termites (of the 20 termites) found on a filterpaper in a petri dish choice test, number of polymer discs interceptedby termite tunnels in a tunneling choice test. Petri dish choice testTunneling choice test Treatment (number of termites) (number ofintercepted discs) Control 3.2 ± 1.2 0 Paper or disc treated 16.8 ± 1.2 6 with fungi decay wood extract

EXAMPLE 3 Impregnation of Polymer Disc with Fungi-Decay Wood Extract

Polymer discs (3.6 cm diameter) were cut out of a meltblownpolypropylene fiber sheet. Acetone solution of fungi-decay wood extractwas pipetted onto each disc to yield a concentration (wt/wt) four timeshigher than those present in fungi decay wood. Control discs weretreated with acetone only. The impregnated polymer discs were air driedfor 24 hrs before testing.

EXAMPLE 4 Tunneling Choice Test for Termites Foraging in Soil Using aTwo-Dimensional Foraging Arena

A choice test was done in a laboratory arena to investigate the effectsof treated polymer discs on termites tunneling in soil. The arena wasconstructed of two sheets of transparent Plexiglas (50×50 cm) separatedfrom each other by four Plexiglas laminas (50×2.5×0.2 cm) placed betweenthe outer margins. As shown in FIG. 2, four access holes (1 cm diameter)were drilled surrounding the center of the upper sheet and covered witha termite release chamber (7). As shown, the chamber was 5 cm high witha 6 cm diameter. A plastic ring spacer (8) (0.2 cm thick, 8 cm diameter,and 1 cm wide) was placed beneath the release chamber to separatetermites from the rest of the arena. The 0.2 cm gaps between thePlexiglas sheets were filled with 400-500 g of sifted sand (150-500 μmsieves; Play Sand Bonsai, Inc.) and moistened with 125-150 ml ofdeionized water. Two hundred fifty workers of the Formosan subterraneantermite (plus 15 soldiers) were released into the chamber and wereforced to follow an artificial tunnel ending in a staggered physicalguide as part of the plastic (9) before exit into the sand in the arena.When encountering a hard object while tunneling in soil, termites followthe object's physical guideline. This experimental device took advantageof termite physical-guideline-following behavior. My previousobservations indicated that when the physical guide ended abruptly, aswas arranged by the sharp tips of the staggered ends, termites continuedto tunnel in the same general direction in the sand. Thus, afterfollowing the provided guide, termites formed a more or less straighttunnel for another 5-10 cm. Two polymer discs, one impregnated withacetone extract of fungi decay wood (10) and other acetone only control(11), were placed 3 cm apart in sand at an equal distance from the endof the physical guide. Termite tunneling geometry was recorded daily,and the number of discs intercepted by termites was counted. Theexperiment was repeated 6 times.

The results showed that in all six experiments (Table I), termitetunnels were directed toward the polymer disc impregnated withfungus-decayed wood extract (12). The results clearly demonstrated thatwhen imbedded in sand, sufficient quantity of “attractants” permeatedout of the treated disc to cause termites to make orientated movementtoward the sources of the attractants.

Subterranean termites forage in soil, and the ability of semiochemicalsintended to “attract” termites have not heretofore been demonstrated tocause termite tunneling to make oriented movement toward the source ofthe attractants. “Attractants” for termites heretofore described in theart typically employed an open air choice test as described in Example1; this only demonstrates palatability or arrestant property of the baitinstead of the ability of a semiochemical to change the direction oftermite tunneling. This is the first time the “attractant” property ofsemiochemicals was demonstrated to cause termites to change theirtunneling direction toward the sources.

EXAMPLE 5 Measuring the Distance of “Attractant” Effects of Fungus-DecayExtract in Soil

The distance by which the impregnated polymer “attracts” termitesforaging in soil was measured using another configuration of the2-dimensional foraging arena. The test was conducted for two termitespecies, Coptotermes formosanus, and eastern subterranean termite,Reticulitermes flavipes. As illustrated by FIG. 3, termites released atthe center chamber (12) were forced to follow a long artificial tunnel(13) to exit at the corner of the arena. Previous observation indicatedthat when termites reached the arena edge, they usually followed theedge guideline, and tunneled more or less in a straight line along theedge (14). Three polymer discs were each imbedded in sand along twosides of the arena, each at distances of 9 cm, 6 cm, and 3 cm from theedge. Three discs at one side were treated with acetone extract offungi-decayed wood as described in Example 3 (10), while the other 3were treated with acetone only (11). The distance between the pointwhere termite tunnel departed from the arena edge (15) and theintercepted disc was measured. The experiment was repeated six timeseach for both C. formosanus and R. flavipes.

Termite tunneling remained along the edge on the sides lined withcontrol discs, while termites tunneled toward at least one of thetreated discs when traveling along the other side lined with treateddiscs (FIG. 3). For C. formosanus, at least one treated disc wasintercepted by termite tunnels for all replicates, while R. flavipesintercepted at least one treated disc for most of the replicates (TableII). The mean distance of the tunneling that departed from the edge tothe treated discs was 9-10 cm for both termite species (Table II). Theseresults demonstrate that semiochemicals of the extract couldpermeate >10 cm (in some replicates >20 cm) from the polymer disc to“attract” termites foraging in soil. Thus, it has been demonstrated thatattractant-impregnated polymers, as part of a monitoring procedure, canbe used to greatly extend the

TABLE II Number of polymer discs intercepted by termite tunnels anddistance (cm) of “attractant” effects of fungal decay extract asmeasured by the tunnel length intercepting a polymer disc. FIGURES aremean (±SE) of 6 replicates for both termite species. Number of Meandistance (cm) of Termite Sp. Treatment intercepted disks interceptedtunnel C. formosanus Control disc 0 ± 0 0 ± 0 Treated disc 1.0 ± 0.6 9.7± 4.7 R. flavipes Control disc 0 ± 0 0 ± 0 Treated disc 0.7 ± 0.5 10.7 ±10.2

REFERENCES

-   Matsumura, F., A. Tai, & H. C. Coppel. 1969. Termite trail-following    substance, isolation and purification from Reticulitermes virginicus    and fungus-infected wood. J. Econ. Entomol. pp. 599-603.-   Metcalf, R. L. & R. A. Metcalf. 1975. Attractants, repellents, and    genetic control in pest management, pp. 275-306, In: Metcalf, R. L.    & W. Luclmann [eds], Introduction to Insect Pest Management, John    Wiley & Sons, New York.-   Shorey, H. H. 1977. Interaction of insects with their chemical    environment, pp. 1-5, In: Shorey, H. H. & J. J. McKelvey, Jr. [eds],    Chemical Control of Insect Behavior, John Wiley & Sons, New York.

I claim:
 1. A method of attracting termites to a bait station, saidmethod comprising the steps of: placing a bait station in soil or on theground in a location that is accessible to termites, and placing atleast one polymeric piece in soil, wherein the bait station holds acellulose source, wherein the at least one polymeric piece is made of anon-cellulose polymer that holds a termite-attracting serniochemicalthat is gradually released into soil to form a serniochemical gradientin the soil when said polymeric piece is deployed in soil, and whereinsaid polymeric piece is external to said bait station so that saidserniochemical gradient leads termites foraging in the area to said baitstation.
 2. The method of claim 1 wherein the polymeric piece isattached to the bait station.
 3. The method of claim 1 wherein thepolymeric piece is in soil within two feet of the bait station.
 4. Themethod of claim 1 wherein the polymeric piece is a sleeve fitted aroundthe bait station.
 5. The method of claim 4 wherein the sleeve is made ofan absorbent foam.
 6. The method of claim 1 wherein the bait station isa hermetically sealed bait pouch made from a flexible materialcontaining therein a toxicant-containing matrix.
 7. The method of claim1 wherein the cellulose source is removable and the bait station is adurable station housing wherein an opening is defined in the durablestation housing and the opening permits the removable cellulose sourceto be placed within said housing and the opening provides above-groundaccess to the cellulose source when the cellulose source is placedwithin said station housing.
 8. The method of claim 7 wherein saidcellulose source is a monitoring device.
 9. The method of claim 7wherein said cellulose source is a toxicant-containing matrix.
 10. Themethod of claim 1 wherein said at least one polymeric piece isimpregnated with said semiochemical.
 11. The method of claim 1 whereinsaid serniochemical is a pheromone.
 12. The method of claim 1 whereinsaid serniochemical is water-soluble.
 13. The method of claim 1 whereinsaid serniochemical is extract of fungal-decayed wood.
 14. Atwo-dimensional testing apparatus for assessing the degree to whichtermites are attracted to a serniochemical in soil, said apparatuscomprising: a first plate and a second plate in a parallelconfiguration, soil between said plates, wherein said plates areseparated by a space small enough to allow termites placed in said soilto travel only in substantially two dimensions in said soil, asubstantially straight physical guide between said plates, and anopening, defined in one of said plates, for placing termites in saidsoil wherein said opening is located so that termites placed in theopening and into the soil must follow said physical guide, said physicalguide extending only partially in said soil so as to allow said termitesto forage freely in any direction in substantially two dimensions aftertraveling along said guide.